Biochemical assessment of preoperative stress: a study with diazepam and measurement of monoamine metabolites and catecholamines in cerebrospinal fluid and plasma.

Diazepam 5 mg or an inert placebo tablet was given as preoperative hypnotic on the night before operation to two groups (n = 18 in each) of healthy women having elective Caesarean section under spinal analgesia. A third group (n = 18) received no hypnotic. The quality of the preoperative night's sleep assessed subjectively was significantly better in the diazepam-treated patients compared with those receiving no drug. The diazepam-treated patients had also smaller CSF concentrations of noradrenaline (NA) and of the dopamine metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC). In comparison with the two other patient groups, in the diazepam group there was no correlation between demographic, physiological or subjectively estimated variables and CSF or plasma measurements of monoamine transmitters and their metabolites. Preoperative fear and apprehension correlated most strongly with preoperative heart rate and with the increase in heart rate from the previous day. The monoamine neurotransmitters or their metabolites were of limited use in monitoring the intensity of preoperative fear and anxiety.